President Obama and Governor Romney have yet to seriously address the climate crisis in their campaigns. And time is running out.

Remember global warming? Yeah, well, judging by the campaigns so far, our presidential candidates don’t. And that’s a big problem because the climate crisis has not gone away. To the contrary, communities around America and the world are already suffering from its impacts, and things continue to get worse.

The basic science behind the climate crisis has been widely understood for decades. Polls show that 97% of practicing climate scientists now view global warming as a serious risk. And the dire consequences of inaction are becoming clearer with each passing year. Earlier in 2012, the Intergovernmental Panel on Climate Change (IPCC), the world’s foremost body on the climate crisis, issued a new, detailed report confirming the connection between climate change and extreme weather events, such as heat waves, droughts, and floods.

Global warming is no longer a future threat; it’s a present reality. And it’s exacerbating and intensifying many of the existing problems we’re already struggling to cope with, including poverty, natural disasters, political instability, and global terrorism.

Now, I’m not into doom and gloom, but the reality around the climate crisis is grim, and hiding from it does no good. Millions of people face hunger/famine and malnutrition around the world today. One to two billion will lack access to clean water this century. Millions are experiencing coastal and inland flooding. And an estimated 200 million will become climate refugees by 2050. This does not take into account those suffering violence from energy and resource-based conflicts, or the drastic impacts the climate crisis is having on the rest of God’s groaning creation. These are some of the tragic consequences of our unsustainable lifestyles and our collective inaction.

The longer we wait to do something, the larger these numbers become, and the harder it will be to turn things around. But it’s not impossible—especially if we start now.

Here’s what we know needs to happen: we need an international treaty with legally binding targets for countries to reduce their global warming pollution to sustainable levels. We know what to aim for: 350ppm (parts per million) is the stable level of atmospheric carbon dioxide; the planet is currently hovering around 400ppm. Moreover, we’ve had success with similar global treaties, such as the Montreal Protocol (which tackles ozone-depleting CFC pollution).

For the world to act, however, America must lead. For America to lead, we need Congress to unite and pass comprehensive climate legislation that centers around putting a price on carbon pollution and also includes addressing deforestation, ocean acidification, and aid for communities to adapt to existing impacts. For Congress to unite, we need two things: 1) a President who will provide strong leadership, and 2) a broad-based movement fighting for this cause.

Scientists tell us that global greenhouse gas emissions must peak and begin to decline during the next presidential administration (specifically, between 2015-2017) if we are to avoid even more catastrophic impacts of climate change. This means that the upcoming election will be the most important one we’ve ever had, or may ever have, when it comes to climate change. It means that it’s crucial for President Obama and Governor Romney to make overcoming the climate crisis a campaign promise and a national priority.

Over the last several years, however, the climate deniers (often propelled with funding from Big Oil and Big Coal) have worked hard to undermine the scientific consensus and turn global warming into a politically toxic issue.

President Obama, once a champion of climate action, has largely gone silent on the issue, and has even begun defensively promoting his support of the fossil fuel industry. He did finally note in a recent Rolling Stone interview that, “I suspect that over the next six months, this (climate change) is going to be a debate that will become part of the campaign, and I will be very clear in voicing my belief that we’re going to have to take further steps to deal with climate change in a serious way.” It was an encouraging step but there’s still a long way to go, and we need to hold the President to his word here.

Governor Romney also once believed in human-caused climate change but, on the way to becoming the Republican Nominee, he flip-flopped under pressure: “My view is that we don’t know what’s causing climate change on this planet. And the idea of spending trillions of dollars to try to reduce CO2 emissions is not the right course for us.” The former governor actively campaigns on his support of the fossil fuel industry and ran a TV ad promising that, if he becomes President, one of his first actions will be to approve the highly controversial Keystone XL oil sands pipeline.

Currently, then, neither of the major candidates is showing the courageous leadership we will need from whoever becomes President after November. This must change, and grassroots groups like 350.org and Young Evangelicals for Climate Action are stepping up to hold them accountable.

In the words of the Rev. Dr. Martin Luther King Jr.: “The ultimate measure of a man is not where he stands in moments of comfort and convenience, but where he stands at times of challenge and controversy.” It is time for the Presidential Candidates to take a stand on the climate crisis. It may be politically tough, but it’s the right and urgent thing to do.

Ben Lowe is on staff with the Evangelical Environmental Network and also serves as the National Spokesperson of Young Evangelicals for Climate Action. A dedicated activist and organizer, Ben was born and raised a missionary kid in Southeast Asia, where he experienced firsthand the impacts of poverty and pollution. He now lives in a refugee and immigrant neighborhood in the Chicagoland area where he ran for U.S. Congress in 2010. Ben is the author of Green Revolution: Coming Together to Care for Creation (IVP 2009) and previously served as National Coordinator for the student creation care network, Renewal.